This invention relates to hydrophobicizing compositions for finishing textiles, to a process for hydrophobicizing textiles and to the use of certain fatty compounds as hydrophobicizing compositions.
Textiles are generally hydrophobicized with hydrophobicizing compositions based on polysiloxanes, fluorocarbons or mixtures of aluminium or zirconium salts with paraffins (cf. xe2x80x9cHandbuch der Textilhilfsmittelxe2x80x9d, A. Chwala, V. Anger, Verlag Chemie, New York 1977, Chapter 3.24 xe2x80x9cPhobiermittelxe2x80x9d, pages 735 et seq). The object of hydrophobicizing textiles, particularly weatherproof clothing, is to make them either water-repellent or impermeable to water. The hydrophobicizing composition is applied to the fibers of the textiles and arranges itself thereon in such a way that the hydrophobic parts of the molecule are perpendicular to the fiber surface. In this way, the tendency of the water to spread over the entire surface is greatly reduced. Under the effect of the cohesion forces, the water assumes the form of spheres and runs off the textile surface in beads.
Although the hydrophobicizing compositions described in the prior art, particularly the paraffin emulsions containing zirconium salts, enable textiles to be adequately hydrophobicized, they are attended by the problem that they are not biodegradable or not sufficiently biodegradable. In addition, where corresponding paraffin emulsions are applied by padding, paraffin deposits are observed on the padding rollers after prolonged operating times so that the rollers have to be cleaned which means an expensive interruption of the production process. Accordingly, there was a need to provide hydrophobicizing compositions which would satisfy all the performance requirements of the textile industry and, in particular, would produce few, if any, deposits on machine parts and at the same time would be biodegradable.
It has now been found that a combination of zirconium salts with certain fatty compounds leads to hydrophobicizing compositions which are as effective in terms of finishing as the paraffin emulsions known per se, but which at the same time also satisfy biodegradability requirements.
In a first embodiment, the present invention relates to a hydrophobicizing composition for finishing textiles which contains a zirconium salt in combination with a fatty compound selected from the group of
a) branched or unbranched, symmetrical or nonsymmetrical dialkyl ethers containing a total of 8 to 44 carbon atoms and/or
b) esters of branched or unbranched C12-22 fatty acids with branched or unbranched C8-22 fatty alcohols and/or
c) branched or unbranched, symmetrical or nonsymmetrical dialkyl ketones containing a total of 8 to 44 carbon atoms.
Suitable zirconium salts are any of the compounds known in the prior art among which zirconium acetate is particularly preferred.
The fatty compounds are alkyl ethers known per se with the general formula R1xe2x80x94Oxe2x80x94R2 where R1 and R2 are each alkyl groups containing 1 to 22 carbon atoms. The total number of carbon atoms in the molecule is 8 to 44. Both symmetrical ethers, i.e. R1 and R2 are identical, and nonsymmetrical ethers (R1xe2x89xa0R2) may be used. The alkyl groups R1 and R2 may be saturated, unsaturated, branched or unbranched. Ethers where R1 and R2 have a carbon chain length of 10 to 22 are particularly preferred. The total number of carbon atoms in the ethers is preferably 0 to 44. Preferred ethers are, for example, dibehenyl ether, distearyl ether, dipalmityl ether and dimyristyl ether. Ethyl hexyl eicosyl ether is mentioned as an example of a nonsymmetrical ether. The ethers may be produced by any known industrial processes. A second group of suitable fatty compounds are esters of branched or unbranched C12-22 fatty acids with branched or unbranched C8-22 fatty alcohols. Suitable fatty acids are, for example, caprylic, pelargonic, capric, undecanoic, tridecanoic, myristic, pentadecanoic, palmitic, heptadecanoic, octadecanoic, nonanoic, arachic or behenic acid. Suitable fatty alcohols are, for example, caprylic, capric, lauryl, myristyl, palmityl, stearyl, arachidyl or behenyl alcohol. As a third group of suitable fatty compounds, the hydrophobicizing compositions may contain dialkyl ketones containing a total of 8 to 44 carbon atoms with the formula R3xe2x80x94COxe2x80x94R4 where R3 and R4 each represent an alkyl group. Both symmetrical ketones (R3=R4) and nonsymmetrical ketones (R3xe2x89xa0R4) may be used. Suitable ketones are, for example, alkyl methyl ketones, such as octanonan-2-one, nonan-2-one, undecan-2-one, dodecan-2-one, tridecan-2-one, tetradecan-2-one, pentadecan-2-one, heptadecan-2-one, octadecan-2-one, nonadecan-2-one, pentadecan-2-one, heptadecan-2-one, octadecan-2-one, nonadecane-2-one, eicosan-2-one or dodecasan-2-one. Symmetrical ketones, such as undecan-6-one, tridecan-7-one, pentadecan-8-one, heptadecan-9-one, nonadecan-10-one, tricosan-12-one, hentriacontan-16-one, pentatriacontan-18-one, nonatriacontan-20-one and triatetracontan-22-one, are also suitable. The ketones can be produced by any methods known to the expert, for example by oxidation or dehydrogenation of secondary alcohols.
The hydrophobicizing compositions according to the invention are preferably present in the form of an aqueous emulsion, water being present in quantities of 10 to 90% by weight. The compositions preferably contain 30 to 80% by weight and more particularly 40 to 60% by weight of water. The zirconium salts are generally present in quantities of 1 to 20% by weight, preferably in quantities of 5 to 15% by weight and more particularly in quantities of 5 to 10% by weight. The fatty compounds a) to c) are preferably present in the compositions in quantities of 10 to 95% by weight, more preferably in quantities of 15 to 60% by weight and most particularly in quantities of 10 to 30% by weight.
If necessary, the compositions may contain other suitable ingredients besides the salts and fatty compounds, more particularly emulsifiers but also nonslip agents, wet strength improvers, feel additives, softeners, solvents, for example ethanol, n-propanol or i-propanol, and pH adjusters, such as organic acids or bases. The pH value of the aqueous emulsions is in the acidic range, preferably below 4.5 and more particularly in the range from 2.0 to 3.5. The auxiliaries are present in small quantities of 0.5 to 5% by weight. In general, the compositions according to the invention contain such auxiliaries in a total quantity of at most 10% by weight.
The compositions according to the invention are produced in known manner by mixing the starting materials with water, heating the resulting mixture to temperatures of 40 to 90xc2x0 C. and then homogenizing the mixture. Average particle sizes of less than 250 nm should be reached. The average particle sizes are in the range from 100 to 200 nm. After cooling, the compositions may be used without further treatment. The compositions are normally applied to the textiles in the form an aqueous emulsion by padding. The compositions according to the invention are suitable for the hydrophobic finishing of textiles of synthetic or natural fibers, more particularly cotton textiles.